Rotary solenoid drive control method

ABSTRACT

A movable body portion Sm is configured to reciprocate in a rotation angle range Zm between a first position Xa and a second position Xb according to energization control of a driving coil  6  and to be stopped at the first position Xa and the second position Xb by a pair of self-holding mechanisms  11   a  and  11   b  by restriction of a pair of restricting stopper mechanisms  10   a  and  10   b  and attraction of magnets  8   a  and  8   b . when controlling switching from the second position Xb (or the first position Xa) to the first position Xa (or the second position Xb), after a driving voltage based on a driving pulse Ps is applied to the driving coil  6 , if the movable body portion Sm has reached a predetermined intermediate position Xp in 10 to 50[%] of the rotation angle range Zm, control is performed so that application of the driving voltage is stopped.

TECHNICAL FIELD

The present invention relates to a rotary solenoid drive control methodsuitable for use in controlling a rotary solenoid.

BACKGROUND ART

Generally, a rotary solenoid having a reciprocating property is used forvarious two-position switching purposes such as switching of a conveyingpath for sorting banknotes or switching of an optical path of an opticaldevice. A rotary solenoid used for such a switching purpose often needsto provide fast operations (high-speed processing) and a reduction insize (thickness) as well as reliability in operation which arecontradictory performances. Generally, a driving device is connected tothe rotary solenoid of this type and a driving pulse to which apredetermined driving voltage is set is supplied to the rotary solenoidwhereby drive control for two-position switching is performed.

Conventionally, a drive control method for use in a rotary solenoiddisclosed in Patent Document 1 as proposed by the present applicant isknown as a drive control method for controlling driving of such a rotarysolenoid. This drive control method controls driving of a rotarysolenoid including a magnet rotor portion in which a magnet portionhaving at least a pair of different poles is provided in a shaft, astator portion having at least a pair of yokes disposed to be fixed to aposition opposing an outer circumferential surface of the magnetportion, a coil unit portion that generates magnetic poles in the yokewith aid of a coil wound around a coil bobbin, an engagement portionformed such that a portion of the magnet portion protrudes in a radialdirection so as to be positioned between the pair of yokes and bedisplaced between edges in a circumferential direction and that a widthin the circumferential direction corresponds to a rotation range, and apair of restricting portions that restricts the position of theengagement portion with the aid of the edges or by making contact withthe engagement portion near the edges. In this drive control method,after a driving voltage is applied to the coil and the magnet rotorportion collides with the engagement portion formed to correspond to therotation range, bouncing decays, and application of the driving voltageis canceled at a timing at which behavior is stabilized.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-80705

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, the conventional drive control method for controlling drivingof a rotary solenoid as well as the drive control method of PatentDocument 1 have the following problems to be solved.

A first problem is that, since control of supplying a current at leastover an entire rotation range, and even after the magnet rotor portionreaches the engagement portion, the current supplying control isperformed until the behavior is stabilized, the influence of atemperature rise of the coil is not negligible. That is, when the rotarysolenoid is continuously used for a long period, the resistance of thecoil increases with increase in the temperature of the coil, and as aresult, the output torque decreases and the stability decreases.Particularly, the decrease in the output torque has a direct influenceon decrease in response speed and the switching speed and becomes afactor that inhibits a fast switching operation (high-speed processing).Moreover, the decrease in the stability is a negative factor from theviewpoint of performing a stable switching operation according to aconstant output torque.

A second problem is that, since electric power is used, it is requestedto reduce power consumption and enhance energy saving properties andcost effectiveness from the viewpoint of saving resources and protectingglobal environment. However, since basic driving control is performed bysimple control of supplying driving pulses, in order to reduce the powerconsumption, it is necessary to decrease an application voltage which isan essential element in realizing an intended operation and to shortenan energization period. As a result, elements to be improved arelimited. Therefore, it cannot be said that sufficient considerations aretaken from the viewpoint of reducing power consumption, and from thisviewpoint, there is a room for further improvements.

An object of the present invention is to provide a rotary solenoid drivecontrol method that solves the problems of such a background art.

Solutions to Problems

In order to solve the above-described problems, a rotary solenoid drivecontrol method according to the present invention is a rotary solenoiddrive control method for controlling driving of a rotary solenoidincluding: a fixed body portion Sc having a casing 2 in which a pair ofbearing portions 3 f and 3 r positioned on front and rear sides areprovided; and a movable body portion Sm having a rotation shaft 4rotatably supported by the pair of bearing portions 3 f and 3 r, whereinthe movable body portion Sm is configured to reciprocate in a rotationangle range Zm between a first position Xa and a second position Xbaccording to energization control of a driving coil 6 and to be stoppedat the first position Xa and the second position Xb by a pair ofself-holding mechanisms 11 a and 11 b by restriction of a pair ofrestricting stopper mechanisms 10 a and 10 b and attraction of magnets 8a, 8 af, . . . , 8 b, 8 bf, and so on, and when controlling switchingfrom the second position Xb (or the first position Xa) to the firstposition Xa (or the second position Xb), after a driving voltage basedon a driving pulse Ps is applied to the driving coil 6, if the movablebody portion Sm has reached a predetermined intermediate position Xp in10 to 50[%] of the rotation angle range Zm, control is performed so thatapplication of the driving voltage is stopped.

In this case, according to a preferred embodiment of the presentinvention, the fixed body portion Sc may include a casing 2 formed of amagnetic material and a driving coil 6 which uses an air-cored coilfixed to an inner surface 2 f (or 2 r) of the casing 2, which is asurface orthogonal to an axial direction Fs of the rotation shaft 4, andthe movable body portion Sm may include a rotor yoke 7 having one end 7s fixed to the rotation shaft 4 and a magnet mechanism portion 8 havinga pair of magnets 8 af and 8 bf fixed to an opposing surface 7 ppositioned on the other end 7 t of the rotor yoke 7, which is a surfaceopposing the driving coil 6, and disposed along a rotation direction Frof the opposing surface 7 p. Moreover, the fixed body portion Sc and themovable body portion Sm may share the restricting stopper mechanisms 10a and 10 b that make contact with each other to restrict the movablebody portion Sm, and the casing 2 may share the self-holding mechanisms11 a and 11 b that attract the movable body portion Sm at the firstposition Xa and the second position Xb. The self-holding mechanisms 11 aand 11 b may preferably use attracting piece portions 11 as and 11 bsthat protrude from a portion of the casing 2.

On the other hand, the movable body portion Sm may include a drivingcoil 6 held by a movable block portion 13 e, the rotation shaft 4 fixedto the movable block portion 13 e and disposed to be arranged inparallel to a center of the driving coil 6, and an attracting piece 16formed of a magnetic material and fixed to a predetermined position ofthe movable block portion 13 e, and the fixed body portion Sc mayinclude a casing 2 formed of a magnetic material, and a magnet mechanismportion 8 having two sets of magnet portions 8 a and 8 b fixed to innersurfaces 2 f and 2 r of the casing 2, disposed to oppose an end in anaxial direction Fs of the driving coil 6, and disposed to correspond tothe first position Xa and the second position Xb of the movable bodyportion Sm. In this case, the magnet portion 8 a or 8 b may be formed ofa single magnet 8 af or 8 bf disposed on one inner surface 2 f of thecasing 2, opposing one end in the axial direction Fs of the driving coil6, and the magnet portion 8 a or 8 b may be formed of a pair of magnets8 af, Bar, 8 bf, and so on disposed on both opposing inner surfaces 2 fand 2 r of the casing 2, opposing both ends in the axial direction Fs ofthe driving coil 6. A cross-sectional area vertical to an axialdirection of the attracting piece 16 may preferably be set to a range of0.1 to 10[%] of a cross-sectional area vertical to an axial direction ofan inner space of the driving coil 6.

Effects of the Invention

According to the rotary solenoid drive control method according to thepresent invention based on such a method provides the followingremarkable effects.

(1) When controlling switching from the second position Xb (or the firstposition Xa) to the first position Xa (or the second position Xb), aftera driving voltage based on a driving pulse Ps is applied to the drivingcoil 6, if the movable body portion Sm has reached a predeterminedintermediate position Xp in 10 to 50[%] of the rotation angle range Zm,control is performed so that application of the driving voltage isstopped. Therefore, it is possible to shorten the energization period Tpremarkably and to extend a non-energization period. As a result, it ispossible to suppress a temperature rise (resistance rise) of the drivingcoil 6 and to avoid decrease in output torque and stability. In thisway, it is possible to secure fast switching operations (high-speedprocessing) which is always necessary while maintaining a high responsespeed and to achieve a stable switching operation. Furthermore, it ispossible to contribute to remarkable reduction in power consumption.

(2) Since the displacement of the movable body portion Sm is based onconstant-speed movement after application of the driving voltage basedon the driving pulse Ps is stopped, it is possible to decrease thenumber and the magnitude of bounces of the movable body portion Sm uponcollision at the first position Xa (or the second position Xb)remarkably. As a result, it is possible to contribute to realizing smallimpact (small vibration) and low noise of the rotary solenoid 1 itself.

(3) According to the preferred embodiment, the fixed body portion Seincludes a casing 2 formed of a magnetic material and a driving coil 6which uses an air-cored coil fixed to an inner surface 2 f (or 2 r) ofthe casing 2, which is a surface orthogonal to an axial direction Fs ofthe rotation shaft 4, and the movable body portion Sm includes a rotoryoke 7 having one end 7 s fixed to the rotation shaft 4 and a magnetmechanism portion 8 having a pair of magnets 8 af and 8 bf fixed to anopposing surface 7 p positioned on the other end 7 t of the rotor yoke7, which is a surface opposing the driving coil 6, and disposed along arotation direction Fr of the opposing surface 7 p. Therefore, it ispossible to eliminate an iron core which is a large component and toreduce the number of components. Moreover, by arranging the center ofthe driving coil 6 to be parallel to the center of the rotation shaft 4,a layout structure which can easily achieve a small size (a smallthickness) can be obtained. Therefore, it is possible to easily realizereduction in the size (particularly, the thickness) of the entire rotarysolenoid 1 and to contribute to reduction in the weight and the cost ofthe entire rotary solenoid 1. Moreover, since the air-cored coil isused, the inductance that is proportional to the permeability in theinner space of the air-cored coil can be decreased to a very small valueof several mH. As a result, since a very fast response speed can berealized in such a way that the current can be raised up to a saturationcurrent substantially instantaneously when a driving voltage is applied,it is possible to realize fast operations and to contribute toimprovement in productivity and processing speed of a target device inwhich the rotary solenoid 1 is used.

(4) According to the preferred embodiment, when the fixed body portionSc and the movable body portion Sm share the restricting stoppermechanisms 10 a and 10 b that make contact with each other to restrictthe movable body portion Sm, since an additional component for formingthe restricting stopper mechanisms 10 a and 10 b is not necessary, it ispossible to reduce the number of components and the number of assemblingsteps and to decrease the size and the cost.

(5) According to the preferred embodiment, when the casing 2 shares theself-holding mechanisms 11 a and 11 b that attract the movable bodyportion Sm at the first position Xa and the second position Xb, since anadditional component that forms the self-holding mechanisms 11 a and 11b is not necessary, it is possible to reduce the number of componentsand the number of assembling steps and to decrease the size and thecost.

(6) According to the preferred embodiment, when the self-holdingmechanisms 11 a and 11 b uses the attracting piece portions 11 as and 11bs that protrude from a portion of the casing 2, since the self-holdingmechanisms 11 a and 11 b can be formed by pressing during fabrication ofthe casing 2, for example, it is possible to fabricate the self-holdingmechanisms 11 a and 11 b easily and to optimize the holding performanceof the self-holding mechanisms 11 a and 11 b easily and flexibly.

(7) According to the preferred embodiment, the movable body portion Smincludes a driving coil 6 held by a movable block portion 13 e, therotation shaft 4 fixed to the movable block portion 13 e and disposed tobe arranged in parallel to a center of the driving coil 6, and anattracting piece 16 formed of a magnetic material and fixed to apredetermined position of the movable block portion 13 e, and the fixedbody portion Sc includes a casing 2 formed of a magnetic material, and amagnet mechanism portion 8 having two sets of magnet portions 8 a and 8b fixed to inner surfaces 2 f and 2 r of the casing 2, disposed tooppose an end in an axial direction Fs of the driving coil 6, anddisposed to correspond to the first position Xa and the second positionXb of the movable body portion Sm. With this configuration, the heavymagnet portions 8 a and 8 b are fixed to the inner surfaces 2 f and 2 rof the casing 2 serving as a fixed side and the relatively light drivingcoil 6 is supported by the rotation shaft 4 serving as a movable side.Therefore, it is possible to decrease an overall weight of the movablebody portion Sm remarkably and to secure a fast response speed and ahigh output torque. Furthermore, since the magnets that form the magnetportions 8 a and 8 b are disposed on the inner surface of the casing 2opposing the end in the axial direction Fs of the driving coil 6supported by the rotation shaft 4, it is possible to increase the sizeof the magnet as long as the arrangement space of the inner surfaces 2 fand 2 r of the casing 2 is allowed. As a result, it is possible torealize overall downsizing of the rotary solenoid 1 while securingnecessary performance.

(8) According to the preferred embodiment, when the magnet portion 8 aand 8 b is formed of a single magnet 8 af and 8 bf disposed on one innersurface 2 f of the casing 2, opposing one end in the axial direction Fsof the driving coil 6, since a minimum necessary number of componentsare used, the rotary solenoid can be implemented as the bestadvantageous form from the viewpoint of reducing the size and the costof the rotary solenoid 1.

(9) According to the preferred embodiment, the magnet portion 8 a and 8b is formed of a pair of magnets 8 af, Bar, 8 bf, and so on disposed onboth opposing inner surfaces 2 f and 2 r of the casing 2, opposing bothends in the axial direction Fs of the driving coil 6. With thisconfiguration, since the number of magnets is doubled as compared to acase in which the magnets 8 af and 8 bf are disposed on one innersurface 2 f of the casing 2, the rotary solenoid can be implemented asthe best advantageous form from the viewpoint of securing the responsespeed, the output torque, the magnetic balance, and the stability of therotary solenoid 1.

(10) According to the preferred embodiment, the cross-sectional areavertical to an axial direction of the attracting piece 16 is set to arange of 0.1 to 10[%] of a cross-sectional area vertical to an axialdirection of an inner space of the driving coil 6. When thecross-sectional area is set in this manner, it is possible to realize astable self-holding action reliably from the viewpoint of securing anattraction force (holding torque) necessary for obtaining a self-holdingforce during stopping and eliminating an unnecessary attraction forceand to optimize the self-holding action easily.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart for describing a rotary solenoid drive controlmethod according to a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram of a control signal used forcontrolling driving of a driving device that can implement the rotarysolenoid drive control method.

FIG. 3 is an electrical circuit diagram illustrating an example of adriving device that can implement the rotary solenoid drive controlmethod.

FIG. 4 is a diagram illustrating time-drive current characteristicsincluding a comparative example when the rotary solenoid is driven bythe driving device.

FIG. 5 is a diagram illustrating time-rotation angle characteristics ofa movable body portion including a comparative example when the rotarysolenoid is driven by the driving device.

FIG. 6 is a diagram for describing the principle of the time-rotationangle characteristics of the movable body portion.

FIG. 7 is a diagram illustrating rotation angle-output torquecharacteristics of the movable body portion including a comparativeexample when the rotary solenoid is driven by the driving device.

FIG. 8 is a cross-sectional rear view at the position of line C-C inFIG. 2, of the rotary solenoid.

FIG. 9 is a cross-sectional side view of the rotary solenoid.

FIG. 10 is a diagram illustrating an inner structure of a fixed bodyportion, illustrating a cover-side inner surface that forms a casing ofthe rotary solenoid.

FIG. 11 is a partially cross-sectional front view illustrating a movablebody portion of the rotary solenoid.

FIG. 12 is an exploded perspective view of the rotary solenoid.

FIG. 13 is a cross-sectional plan view including an enlarged view of aportion of the rotary solenoid.

FIG. 14 is a diagram illustrating a distribution of magnetic lines offorce when the rotary solenoid is stopped.

FIG. 15 is a cross-sectional side view illustrating a modification ofthe rotary solenoid.

FIG. 16 is a cross-sectional rear view at the position of line D-D inFIG. 17, of a rotary solenoid according to a second embodiment of thepresent invention.

FIG. 17 is a cross-sectional side view of the rotary solenoid.

FIG. 18 is a schematic view of installation seen from a front side,illustrating a use example of the rotary solenoid according to the firstand second embodiments of the present invention.

FIG. 19 is a schematic view of installation seen from a lateral side,illustrating a use example of the rotary solenoid.

REFERENCE SIGNS LIST

1: Rotary solenoid, 2: Casing, 2 f: Inner surface of casing, 2 r: Innersurface of casing, 3 f: Bearing portion, 3 r: Bearing portion, 4:Rotation shaft, 6: Driving coil, 7: Rotor yoke, 7 s: One end of rotoryoke, 7 t: Other end of rotor yoke, 7 f: Opposing surface, 8: Magnetmechanism portion, 8 a: Magnet portion, 8 b: Magnet portion, 8 af:Magnet, 8 bf: Magnet, 8 ar: Magnet, 10 a: Restricting stopper mechanism,10 b: Restricting stopper mechanism, 11 a: Self-holding mechanism, 11 b:Self-holding mechanism, 11 as: Attracting piece portion, 11 bs:Attracting piece portion, 13 e: Movable block portion, 16: Attractingpiece, Sc: Fixed body portion, Sm: Movable body portion, Xa: Firstposition, Xb: Second position, Xp: Intermediate position, Zm: Rotationangle range, Ps: Driving pulse, Fs: Axial direction, Fr: Rotationdirection

BEST MODE FOR CARRYING OUT THE INVENTION

Next, a preferred embodiment according to the present invention will bedescribed in detail based on the drawings.

First, a rotary solenoid 1 according to preferred first and secondembodiments will be described with reference to FIGS. 8 to 19 using adrive control method according to the present invention.

First Embodiment

First, the rotary solenoid 1 according to the first embodiment will bedescribed with reference to FIGS. 8 to 15. The rotary solenoid 1 roughlyincludes a fixed body portion Sc having a casing 2 in which a pair ofbearing portions 3 f and 3 r positioned on front and rear sides areprovided and a movable body portion Sm having a rotation shaft 4rotatably supported by the pair of bearing portions 3 f and 3 r.

The fixed body portion Sc includes the casing 2 illustrated in FIGS. 8and 9, and the casing 2 includes a frame portion 2 m having an openfront surface and a lid portion 2 c that covers the open surface of theframe portion 2 m. In this case, an inner surface of the lid portion 2 cserves as a front-side inner surface 2 f of the casing 2, and an innersurface of the frame portion 2 m opposing (facing) the inner surface 2 fserves as a rear-side inner surface 2 r of the casing 2. A heightdimension of the casing 2 illustrated in FIG. 8 is 16 [mm].

The frame portion 2 m is formed in a box form having an open frontsurface using a soft magnetic steel plate (a magnetic material) such asa cold rolled steel plate. In this case, the plate thickness can bereduced further when pure iron or a silicon steel plate having a highsaturation magnetic flux density is used. On the other hand, when thethickness of the steel plate is set to approximately half (0.5 to 2.0[mm]) (that is, a relatively large thickness) of the thickness of themagnet 8 af (8 bf), it is possible to prevent saturation of a magneticcircuit of the yoke and to suppress leakage of magnetic fluxes due tosaturation. In addition, since a vibration (amplitude) when the movablebody portion Sm collides with a certain component can be suppressed, itis also possible to contribute to reduction in collision sound.

A bearing attachment hole is formed at an upper position of the innersurface 2 r of the frame portion 2 m and the rear-side bearing portion 3r formed in a ring form is attached to the bearing attachment hole. Inthis case, since the movable body portion Sm is attracted toward thefront side (toward the lid portion 2 c), relatively large stress is notapplied to the rear-side bearing portion 3 r, and large mechanicalstrength is not required for the bearing portion 3 r. Therefore, asynthetic resin material can be used as a material for forming thebearing portion 3 r, and the thickness in the axial direction Fs can bereduced.

On the other hand, the lid portion 2 c can be formed using a materialsimilar to that of the frame portion 2 m, except that the lid portion 2c is formed in a form of one piece of plate. Moreover, a circularattachment hole is formed at an upper position of the inner surface 2 fof the lid portion 2 c and the front-side bearing portion 3 f formed ina ring form is attached to the circular attachment hole. As describedabove, since the movable body portion Sm is attracted toward the frontside (toward the lid portion 2 c) by a magnetic circuit, the bearingportion 3 f needs to secure mechanical strength sufficient for resistingagainst this stress. Therefore, the bearing portion 3 f is formedintegrally using a metallic material and has a large thickness in theaxial direction Fs. The lid portion 2 c is firmly fixed by welding,caulking, or the like.

In this way, when the frame portion 2 m is assembled with the lidportion 2 c, a plurality of (in this example, four) caulking pieceportions 2 mp formed to protrude from an opening edge of the frameportion 2 m may be bent (see FIG. 11) to press concave portions 2 cpformed in the lid portion 2 c. In this manner, the casing 2 can beeasily assembled by the frame portion 2 m and the lid portion 2 c, andthe casing 2 forms a portion of a magnetic circuit (a magnetic path)that magnetic lines of force from magnets 8 af and 8 bf to be describedlater pass through.

On the other hand, since the lid portion 2 c functions substantially asthe fixed body portion Sc, a rectangular fixed block portion 12integrally molded using a synthetic resin material which is aninsulating material (a non-magnetic material) is fixed to a lowerposition of the inner surface 2 f of the lid portion 2 c. In this case,as illustrated in FIG. 5, a plurality of pin-shaped convex portions 12 pare formed on an attachment surface of the fixed block portion 12 andthe convex portions 12 p are inserted to the concave portions 2 fcformed in the lid portion 2 c. In this way, positioning of the fixedblock portion 12 with respect to the lid portion 2 c is realized, andthe distal ends of the inserted convex portions 12 p are fixed bythermal deformation or the like. The use of the fixed block portion 12is not essential. For example, a steel substrate which is formed of asteel plate such as an electro-galvanized zinc plated steel plate and inwhich an insulating layer such as a polyimide layer is formed on asurface of the steel plate and a copper pattern is formed on theinsulating layer may be used as the lid portion 2 c. By doing so,electrical connection with lead wires or an driving coil 6 to bedescribed later or mounting of a circuit component Pc such as a thermalfuse can be realized on the inner surface 2 f of the lid portion 2 c,which contributes to reduction in the number of assembling steps.

A coil supporting convex portion 12-1 and 12-2 inserted to an innerspace of the driving coil 6 which uses an air-cored coil to position andfix the driving coil 6 is integrally formed to protrude from a centralposition of the fixed block portion 12, and a component holding portion14 for holding one or two or more circuit components Pc connected to thedriving coil 6 is integrally formed in a portion of the fixed blockportion 12 where the driving coil 6 is not positioned as illustrated inFIG. 10. The component holding portion 14 can be formed in a channelform.

In this manner, when the fixed block portion 12 formed of a non-magneticmaterial, holding the driving coil 6 is provided in the fixed bodyportion Sc, the driving coil 6 can be positioned at an accurate positionby the fixed block portion 12 and can be easily assembled with respectto the casing 2. Furthermore, when the component holding portion 14 isformed integrally with the fixed block portion 12, since the circuitcomponent Pc can be held (fixed) at a predetermined position of thefixed block portion 12 adjacent to the driving coil 6, it is possible toavoid troubles such as open-circuit on an energization circuit includinglead wires drawn from the driving coil 6 and to contribute toimprovement in reliability.

The driving coil 6 is prepared as follows. The driving coil 6 is asingle air-cored coil around which a magnet wire (an annealed copperwire) is wound. In the first embodiment, as illustrated in FIG. 10, thedriving coil 6 is formed in such a shape that a circular coil isdeformed in an approximately rectangular form (a trapezoidal form). Inthis case, the driving coil 6 is preferably exposed to hot air ofseveral hundreds of temperature [° C.] to achieve thermal welding sothat adhesion strength between magnet wires is secured. When thethermally welded driving coil 6 is pressed in a thickness direction, aspace factor of a conductor (that is, an ampere turn) can be increased.Therefore, it is possible to contribute to reduction in thickness of theentire rotary solenoid 1, and to further increase the ampere turn when aflat wire is used as the magnet wire.

The driving coil 6 is attached to the fixed block portion 12 and isfixed by an adhesive or the like, and the circuit component Pc isaccommodated in the component holding portion 14 and is fixed by anadhesive or the like. The driving coil 6 and the circuit component Pcare connected and are connected to lead wires whereby a lid portion 2 cside assembly is obtained. The illustrated circuit component Pc is athermal fuse connected in series to the driving coil 6. Moreover, thecircuit component Pc also includes lead wires (lead-out wires of thedriving coil 6).

On the other hand, the movable body portion Sm includes the rotationshaft 4 rotatably supported by the pair of bearing portions 3 f and 3 rprovided in the casing 2. The rotation shaft 4 is formed of a metallicmaterial having high rigidity such as a stainless material. The materialmay be a magnetic material or a non-magnetic material. When a magneticmaterial is used, the rotation shaft 4 can be used as a part of amagnetic circuit of the rotary solenoid 1.

One end of the movable block portion 13 integrally molded using asynthetic resin material which is an insulating material (a non-magneticmaterial) is fixed onto the rotation shaft 4. Although it is preferableto form the movable block portion 13 using a synthetic resin materialfrom the viewpoint of decreasing the moment of inertia as much aspossible, a metallic material having a small specific gravity such asaluminum or magnesium may be used. Particularly, when a PA resinmaterial such as a nylon material is used as the synthetic resinmaterial, a vibration absorbing effect is obtained. When magnesiumhaving a weight equivalent to the synthetic resin material is used asthe metallic material, it is possible to obtain a vibration absorbingeffect while securing high strength.

The movable block portion 13 includes a cylindrical upper block part 13u positioned in an upper part and a flat plate-shaped lower block part13 d extended downward from a central position in the axial direction Fsof the upper block part 13 u. The movable block portion 13 is fixed in astate in which an intermediate portion of the rotation shaft 4 passesthrough the upper block part 13 u. In this case, the movable blockportion 13 can be fixed by press-fitting, welding, or the like. A ridgedpattern or the like is preferably formed on a circumferential surface ofthe rotation shaft 4 that fixes the upper block part 13 u to therebyincrease the fixing strength further.

A rotor yoke 7 having a shape smaller than but similar to the movableblock portion 13 is arranged on a rear surface of the movable blockportion 13. In this way, one end (an upper end) 7 s of the rotor yoke 7is fixed to the rotation shaft 4. The rotor yoke 7 can be formed of onepiece of plate which is funned of a soft magnetic steel plate (amagnetic material) such as a cold rolled steel plate and of which thethickness Lp is set to approximately half the thickness Lm in the axialdirection Fs of the magnets 8 af and 8 bf. In this case, the thicknessLp of the rotor yoke 7 in a portion where the magnetic fluxes betweenthe magnets 8 af and 8 bf concentrate the most is preferably set to besmall such that the rotor yoke 7 can be used even if magnetic fluxessaturate by taking a magnetic circuit associated with the adjacentcasing 2 to consideration. In this way, it is possible to improve theefficiency of a magnetic circuit and to contribute to reducing the sizeand the thickness.

A magnet mechanism portion 8 made up of the pair of magnets 8 af and 8bf is fixed to an opposing surface 7 p opposing the driving coil 6 asillustrated in FIG. 9, on the side of the other end 7 t of the rotoryoke 7 positioned in the lower block part 13 d. In this case, themagnets 8 af and 8 bf are formed in a flat rectangular solid form ofwhich the thickness is set to Lm and are arranged at a predeterminedinterval along a rotation direction Fr (that is, a turning direction) ofthe opposing surface 7 p. As illustrated in FIG. 9, the magnets 8 af and8 bf pass through the movable block portion 13 and are exposed to thefront surface of the movable block portion 13. One of the magnetsurfaces of each of the exposed magnets 8 af and 8 bf serves as the Npole and the other magnet surface serves as the S pole.

A ferrite magnet, a rare-earth magnet, and the like can be used for themagnets 8 af and 8 bf but there is no particular limitation thereto. Asan example, when a [Nd—Fe—B] magnet is used, since a high air-gapmagnetic flux density is obtained, it is possible to increase the outputtorque and to further increase the magnetic flux density at the air gapby making the most of magnetic characteristics when the magnet isoriented (magnetized) in a thickness direction. When the thickness Lm ofthe magnets 8 af and 8 bf is set to approximately 2 to 4 [mm] and theair gap is set to approximately 4 to 8 [mm] that is twice the thickness,it is possible to obtain a permeance coefficient of 0.5 or larger and toobtain an air-gap magnetic flux density of 0.5 [T] or larger. A singlemagnet can be used as the pair of magnets 8 af and 8 bf, andparticularly, a single magnet in which two poles are magnetized in adivided manner in a planar direction can also be used as the pair ofmagnets 8 af and 8 bf.

As described above, since the movable body portion Sm includes therotation shaft 4, the movable block portion 13, the rotor yoke 7, andthe magnets 8 af and 8 bf, these components may be assembled to obtainthe movable body portion Sm. The rotation shaft 4, the rotor yoke 7, andthe magnets 8 af and 8 bf may be insert-molded when the movable blockportion 13 is molded. When such a movable block portion 13 is provided,the rotation shaft 4, the rotor yoke 7, and the magnet mechanism portion8 can be integrated using the movable block portion 13 which can beformed of a synthetic resin material or the like as a base. Therefore,it is possible to fabricate the movable body portion Sm easily byinsert-molding and to improve the fixing strength (rigidity) between therotation shaft 4, the rotor yoke 7, and the magnet mechanism portion 8and to improve the positioning accuracy.

On the other hand, a pair of restricting stopper mechanisms 10 a and 10b for restricting a rotation angle range Zm of the movable body portionSm is provided inside the casing 2. In this case, the pair ofrestricting stopper mechanism 10 a and 10 b are shared for the fixedbody portion Sc and the movable body portion Sm. Specifically, asillustrated in FIG. 8, one side surface in the rotation direction Fr ofthe movable block portion 13 that forms the movable body portion Sm isformed as a restricting surface portion 13 a and the other side surfaceis formed as a restricting surface portion 13 b. Due to this, when themovable body portion Sm is rotated toward one side (toward a firstposition Xa), the restricting surface portion 13 a makes contact withone inner surface 2 a of the casing to restrict the rotation. When themovable body portion Sm is rotated toward the other side (toward asecond position Xb), the restricting surface portion 13 b makes contactwith the other inner surface 2 b of the casing 2 to restrict therotation. Therefore, one restricting surface portion 13 a of the movablebody portion Sm and one inner surface 2 a of the fixed body portion Scform one restricting stopper mechanism 10 a, and the other restrictingsurface portion 13 b of the movable body portion Sm and the other innersurface 2 b of the fixed body portion Sc form the other restrictingstopper mechanism 10 b.

In this way, when the pair of restricting stopper mechanisms 10 a and 10b that make contact with each other to restrict the rotation angle rangeZm of the movable body portion Sm are shared for the fixed body portionSc and the movable body portion Sm, since an additional component forforming the restricting stopper mechanisms 10 a and 10 b is notnecessary, it is possible to reduce the number of components and thenumber of assembling steps and to decrease the size and the cost.Particularly, when the pair of restricting surface portions 13 a and 13b that make contact with the inner surfaces 2 a and 2 b of the casing 2to form the restricting stopper mechanisms 10 a and 10 b are provided inthe movable block portion 13, since a portion of the movable blockportion 13 which can be formed of a synthetic resin material or the likecan be used as the restricting surface portions 13 a and 13 b, it ispossible to form the restricting stopper mechanisms 10 a and 10 b easilyand to set the rotation angle range Zm of the movable block portion 13easily. In FIG. 11, the movable body portion Sm at the position wherethe movable body portion Sm is restricted by the restricting stoppermechanisms 10 a and 10 b is indicated by an imaginary line. Therefore,the rotation angle range Zm of the movable body portion Sm is a range inwhich the movable body portion Sm is restricted by the pair ofrestricting stopper mechanisms 10 a and 10 b, and the positions at whichthe movable body portion Sm is restricted by the pair of restrictingstopper mechanisms 10 a and 10 b are the first position Xa and thesecond position Xb at both ends of the rotation angle range Zm.

Self-holding mechanisms 11 a and 11 b that attract the movable bodyportion Sm at the first and second positions Xa and Xb to hold theposition of the movable body portion Sm are provided inside the casing2. In the illustrated example, the self-holding mechanisms 11 a and 11 bare shared by the casing 2. Specifically, as illustrated in FIGS. 10 and13, a pair of cut-in portions 21 and 22 are formed in an edge of the lidportion 2 c that forms the casing 2, and a strip-shaped piece formedbetween the cut-in portions 21 and 22 is bent toward the inner side at90 [° ] to form one attracting piece portion 15 as. In this way, oneself-holding mechanism 11 a is formed such that, when the movable bodyportion Sm is rotated toward the first position Xa, one magnet 8 afapproaches the attracting piece portion 11 as, and the movable bodyportion Sm is held at the first position Xa by the attraction of themagnet 8 af and the attracting piece portion 11 as. The otherself-holding mechanism 11 b is formed similarly to one self-holdingmechanism 11 a except that the self-holding mechanism 11 b isbilaterally symmetrical to the self-holding mechanism 11 a. Referencenumeral 11 bs indicates an attracting piece portion of the otherself-holding mechanism 11 b.

Therefore, since the movable body portion Sm includes the magnets 8 afand 8 bf, the attracting piece portions 11 as and 11 bs formed in thecasing 2 form the pair of self-holding mechanisms 11 a and 11 b and thecasing 2 shares the pair of self-holding mechanisms 11 a and 11 b. Inthis manner, when the pair of self-holding mechanisms 11 a and 11 b areshared by the casing 2, since an additional component that forms theself-holding mechanisms 11 a and 11 b is not necessary, it is possibleto reduce the number of components and the number of assembling stepsand to decrease the size and the cost. Particularly, when theself-holding mechanisms 11 a and 11 b are formed using the attractingpiece portions 11 as and 11 bs that protrude a portion of the casing 2,the self-holding mechanisms 11 a and 11 b can be formed by pressingduring fabrication of the casing 2, for example. Therefore, it ispossible to fabricate the self-holding mechanisms 11 a and 11 b easilyand to optimize the holding performance of the self-holding mechanisms11 a and 11 b easily and flexibly.

Since the rotary solenoid 1 according to the first embodiment has arelatively simple structure (for example, the use of the air-cored coil(the driving coil 6), detailed dimensions are important factors.Hereinafter, particularly important factors associated with thedimensions of respective portions will be described with reference toFIG. 13.

First, a shortest distance Ls in the axial direction Fs between themagnet 8 af and the attracting piece portion 11 as (specifically, theshortest distance Ls between the attracting piece portion 11 as and themagnet 8 af of the movable body portion Sm at the first position Xa) isset to be smaller than the thickness Lm of the magnet 8 af in the axialdirection Fs. Moreover, the shortest distance Ls in the axial directionFs between the magnet 8 bf and the attracting piece portion 11 bs(specifically, the shortest distance Ls between the attracting pieceportion 11 bs and the magnet 8 bf of the movable body portion Sm at thesecond position Xb) is set to be smaller than the thickness Lm of themagnet 8 bf in the axial direction Fs. When such conditions areselected, it is possible to secure a sufficient self-holding functionwhen configuring the self-holding mechanisms 11 a and 11 b under theconditions and to easily optimize the self-holding function.

The magnet 8 af and the attracting piece portion 11 as are disposed insuch a positional relation that these components do not overlap eachother in the axial direction Fs, and the magnet 8 bf and the attractingpiece portion 11 bs are disposed in such a positional relation thatthese components do not overlap each other in the axial direction Fs.Specifically, a gap Lg (Lg>0) is formed between the magnet 8 af and theattracting piece portion 11 as in the axial direction Fs, and the gap Lgis formed between the magnet 8 bf and the attracting piece portion 11bs. When such positional conditions are selected, since a vector balanceof the attracting force of the magnets 8 af and 8 bf and the attractingpiece portions 11 as and 11 bs can be optimized under this positionalrelation, it is possible to secure a satisfactory self-holding functionof the self-holding mechanisms 11 a and 11 b.

A shortest distance Ly between an end in the rotation direction Fr ofthe rotor yoke 7 and the inner surface 2 a of the casing 2 at the firstposition Xa and a shortest distance Li between an end in the rotationdirection Fr of the magnet 8 af and the inner surface 2 a of the casing2 at the first position Xa are set to be smaller than the thickness Lmof the magnet 8 af in the axial direction Fs. Moreover, the shortestdistance Ly between an end in the rotation direction Fr of the rotoryoke 7 and the inner surface 2 b of the casing 2 at the second positionXb and the shortest distance Li between an end in the rotation directionFr of the magnet 8 bf and the inner surface 2 b of the casing 2 at thesecond position Xb are set to be smaller than the thickness Lm of themagnet 8 bf in the axial direction Fs. When such conditions areselected, since the magnetic circuit of the rotary solenoid 1 accordingto the present invention can be constructed in an optimal form, it ispossible to secure satisfactory magnetic properties due to the selecteddimensions.

A distance La between the rotor yoke 7 and the inner surface 2 r of thecasing 2 facing the rotor yoke 7 is set to be smaller than a thicknessLc of the casing 2 in the inner surface 2 r. When the distance is set inthis manner, since the rotor yoke 7 and the casing 2 can function as anintegrated complementary magnetic path, it is possible to construct asatisfactory magnetic circuit capable of suppressing magnetic leakage asmuch as possible.

Next, a method of manufacturing the rotary solenoid 1 according to thefirst embodiment will be described with reference to FIG. 12.

FIG. 12 illustrates an exploded perspective view of the rotary solenoid1 according to the first embodiment. As understood from FIG. 12,respective components can be assembled along the axial direction Fs.

First, the assembly of the lid portion 2 c is fixed (attached) bywelding, caulking, or the like by fitting the bearing portion 3 f to thecircular attachment hole formed at the upper position of the lid portion2 c from the outer surface side along the axial direction Fs. Moreover,after the fixed block portion 12 is assembled with the inner surface 2 fof the lid portion 2 c along the axial direction Fs and the plurality ofconvex portions 12 p are inserted to the concave portions 2 fc, thedistal ends of the convex portions 12 p are fixed by thermal deformationor the like. Furthermore, the cold rolled steel plate 12-1 and 12-2 ofthe fixed block portion 12 is inserted to the inner space of the drivingcoil 6 from the axial direction Fs, and the circuit component Pc isinserted to the component holding portion 14 from the axial directionFs. In this way, the assembly of the lid portion 2 c can be obtained.

On the other hand, as described above, the assembly of the movable bodyportion Sm may be integrally molded by insert molding and may befabricated by an ordinary assembling method. In the case of theassembling method, the rotor yoke 7 is assembled with the rear surfaceof the movable block portion 13 which is a resin molded component fromthe axial direction Fs, and after that, the magnets 8 af and 8 bf areassembled from the surface side of the movable block portion 13 alongthe axial direction Fs. Moreover, the rotation shaft 4 is inserted andfixed to the movable block portion 13 from the axial direction Fs. Inthis way, the assembly of the movable body portion Sm can be obtained.

On the other hand, the bearing portion 3 r is attached to the circularattachment hole formed at the upper position of the frame portion 2 mfrom the inner surface side along the axial direction Fs. After that,the rotation shaft 4 of the movable body portion Sm is inserted to thebearing portion 3 r from the rear end side from the axial direction Fs,and the front end side of the rotation shaft 4 is inserted to thebearing portion 3 f fixed to the lid portion 2 c from the inner surfaceside along the axial direction Fs. When four caulking piece portions 2mp that protrude from the frame portion 2 m are bent (caulked) and theconcave portions 2 cp of the lid portion 2 c are pressed and fixed, therotary solenoid 1 according to the present embodiment illustrated inFIGS. 8 and 9 can be obtained.

When the rotary solenoid 1 is assembled (manufactured) in this manner,since the respective components can be assembled along the axialdirection Fs, it is possible to realize full automation of themanufacturing steps extremely easily and to contribute to reduction inthe manufacturing cost.

Therefore, the rotary solenoid 1 according to the present embodiment isconstructed by a basic structure in which the fixed body portion Scincludes the driving coil 6 and the movable body portion Sm includes therotor yoke 7 having one end 7 s fixed to the rotation shaft 4 and themagnet mechanism portion 8 having the pair of magnets 8 af and 8 bffixed to the opposing surface 7 p positioned close to the other end 7 tof the rotor yoke 7 serving as a surface opposing the driving coil 6 anddisposed along the rotation direction Fr of the opposing surface 7 p.Therefore, it is possible to eliminate an iron core which is a largecomponent and to reduce the number of components. Moreover, by arrangingthe center of the driving coil 6 to be parallel to the center of therotation shaft 4, a layout structure which can easily achieve a smallsize (a small thickness) can be obtained. Therefore, it is possible toeasily realize reduction in the size (particularly, the thickness) ofthe entire rotary solenoid 1 and to contribute to reduction in theweight and the cost of the entire rotary solenoid 1.

Since the driving coil 6 is used, the inductance that is proportional tothe permeability in the inner space of the driving coil 6 can bedecreased to a very small value of several mH. As a result, since a veryfast response speed can be realized in such a way that the current canbe raised up to a saturation current substantially instantaneously whena driving voltage is applied, it is possible to realize fast operationsand to contribute to improvement in productivity and processing speed ofa target device in which the rotary solenoid 1 is used.

FIG. 15 illustrates a modification of the rotary solenoid 1 according tothe first embodiment. In the modification illustrated in FIG. 15, thearrangement of components is reversed in a front-to-rear relation alongthe axial direction Fs with respect to the rotary solenoid 1 illustratedin FIG. 9.

That is, in the embodiment illustrated in FIG. 9, the driving coil 6 isfixed to the inner surface 2 f of the lid portion 2 c which is on thefront side, and the movable body portion Sm having the magnets 8 af and8 bf is disposed on the rear side. Therefore, the movable body portionSm is attracted toward the front side, and stress resulting fromattraction acts on the bearing portion 3 f on the front side. Due tothis, it is necessary to increase the mechanical strength of the bearingportion 3 f. On the other hand, the mechanical strength of the bearingportion 3 r on the rear side can be suppressed to be low.

In contrast, in the modification illustrated in FIG. 15, the drivingcoil 6 is fixed to the inner surface 2 r of the frame portion 2 m whichis on the rear side, and the movable body portion Sm having the magnets8 af and 8 bf is disposed on the front side. Therefore, in this case,the movable body portion Sm is attracted toward the rear side and stressresulting from attraction acts on the bearing portion 3 r on the rearside. Due to this, it is necessary to increase the mechanical strengthof the bearing portion 3 r on the rear side, and in this modification,the same component as the front-side bearing portion 3 f is assembledwith the rear-side bearing portion 3 r. Although an inner-side stress isnot applied to the front-side bearing portion 3 f, an outer-side load asa working end is applied. Due to this, although this modification alsocannot simplify the bearing portion 3 f, a stress distribution can beequally distributed in a front-rear direction. The other detailedstructure of FIG. 15 is the same as that of the embodiment illustratedin FIG. 9. Due to this, in the modification illustrated in FIG. 15, thesame portions as those of FIG. 9 are denoted by the same referencenumerals to clarify the configuration, and the detailed descriptionthereof will be omitted.

Second Embodiment

Next, a rotary solenoid 1 according to a second embodiment will bedescribed with reference to FIGS. 16 and 17.

The rotary solenoid 1 according to the second embodiment is the rotarysolenoid 1 illustrated in FIG. 9 in which the fixed body portion Sc isformed by attaching the magnet mechanism portion 8 to the casing 2 andthe movable body portion Sm is formed by attaching the driving coil 6 tothe rotation shaft 4.

Specifically, the movable body portion Sm includes the driving coil 6held by a movable block portion 13 e, the rotation shaft 4 fixed to themovable block portion 13 e and disposed to be arranged in parallel tothe center of the driving coil 6, and an attracting piece 16 formed of amagnetic material fixed to a predetermined position of the movable blockportion 13 e. On the other hand, the fixed body portion Sc includes thecasing 2 formed of a magnetic material and a magnet mechanism portion 8having two sets of magnet portions 8 a and 8 b fixed to the innersurfaces 2 f and 2 r of the casing 2 and disposed to oppose an end inthe axial direction Fs of the driving coil 6 so as to correspond to thefirst position Xa and the second position Xb of the movable body portionSm.

With this configuration, the heavy magnet portions 8 a and 8 b are fixedto the inner surfaces 2 f and 2 r of the casing 2 serving as a fixedside and the relatively light driving coil 6 is supported by therotation shaft 4 serving as a movable side. Therefore, it is possible todecrease an overall weight of the movable body portion Sm remarkably andto secure a fast response speed and a high output torque. Furthermore,since the magnets that form the magnet portions 8 a and 8 b are disposedon the inner surface of the casing 2 opposing the end in the axialdirection Fs of the driving coil 6 supported by the rotation shaft 4, itis possible to increase the size of the magnet as long as thearrangement space of the inner surfaces 2 f and 2 r of the casing 2 isallowed. As a result, it is possible to realize overall downsizing ofthe rotary solenoid 1 while securing necessary performance.

The magnet mechanism portion 8 illustrated in FIGS. 16 and 17 is made upof the pair of magnets 8 af and 8 bf disposed on the inner surfaces 2 fand 2 r on both opposing sides of the casing 2, opposing both ends inthe axial direction Fs of the driving coil 6 when forming the magnetportions 8 a. That is, one magnet portion 8 a is made up of a pair ofmagnets 8 af and Bar opposing each other, and the other magnet portion 8b is made up of a pair of magnets 8 bf and 8 br opposing each other.Since the magnet 8 br is fixed to the inner surface 2 r of the casing 2and is disposed to oppose the magnet 8 af fixed to the inner surface 2 fof the casing, the magnet 8 br is not depicted in the drawing.

With this configuration, since the number of magnets is doubled ascompared to a case in which the magnets 8 af and 8 bf are disposed onone inner surface 2 f of the casing 2, the rotary solenoid 1 can beimplemented as the best advantageous form from the viewpoint of securingthe response speed, the output torque, the magnetic balance, and thestability of the rotary solenoid 1.

On the other hand, although not illustrated in the drawing, similarly tothe first embodiment illustrated in FIG. 9, the magnet mechanism portion8 may be made up of the single magnets 8 af and 8 bf disposed on oneinner surface 2 f (or 2 r) of the casing 2 opposing one end in the axialdirection Fs of the driving coil 6. In this case, since a minimumnecessary number of components are used, the rotary solenoid can beimplemented as the best advantageous form from the viewpoint of reducingthe size and the cost of the rotary solenoid 1.

On the other hand, the attracting piece 16 and the magnet mechanismportion 8 (the magnet portions 8 a and 8 b) form the pair ofself-holding mechanisms 11 a and 11 b by attraction of the magnetmechanism portion 8. In this case, a cross-section area vertical to theaxial direction of the attracting piece 16 is preferably set to a rangeof 0.1 to 10[%] of the cross-sectional area vertical to the axialdirection in the inner space of the driving coil 6. When thecross-sectional area is set in this manner, it is possible to realize astable self-holding action reliably from the viewpoint of securing anattraction force (holding torque) necessary for obtaining a self-holdingforce during stopping and eliminating an unnecessary attraction forceand to optimize the self-holding action easily.

In FIGS. 16 and 17, reference numeral 13 ea indicates a restrictingsurface portion formed integrally with the movable block portion 13 ethat forms the restricting stopper mechanism 10 a, and reference numeral13 eb indicates a restricting surface portion formed integrally with themovable block portion 13 e that forms the restricting stopper mechanism10 b. Reference numerals 62 s and 62 t indicate a pair of lead wiresdrawn from the driving coil 6, and reference numerals 61 s and 61 tindicate holding slit portions formed in the movable block portion 13 eholding the lead wires 62 s and 62 t. The other basic structure issimilar to that of the rotary solenoid 1 illustrated in the firstembodiment. Therefore, in FIGS. 16 and 17, the same portions (samefunctional portions) as those of FIGS. 8 and 9 will be denoted by thesame reference numerals to clarify the configuration, and the detaileddescription thereof will be omitted.

Basic Operation and Use Method

Next, a basic operation and a use method of the rotary solenoid 1according to the first and second embodiments will be described withreference to FIGS. 1 to 7 (FIG. 14). FIGS. 1 to 7 (FIG. 14) illustrate acase in which the control method is applied to the rotary solenoid 1 ofthe first embodiment.

FIG. 3 illustrates an example of a driving device 30 suitable for use inthe rotary solenoid 1. In FIG. 3, reference numeral 6 indicates adriving coil, and in this case, includes a circuit component (a thermalfuse or the like) Pc. In the rotary solenoid 1, since two lead wires areled out from the driving coil 6, the lead wires are connected to thedriving device 30. The driving device 30 includes a driving circuit 31connected to two lead wires, a DC power supply 32 that supplies DC power(DC 24 [V]) to the driving circuit 31, and a switching pulse generationunit 33 that applies a first switching pulse Pa and a second switchingpulse Pb to the driving circuit 31, and an adjustment unit 34 connectedto the switching pulse generation unit 33 to adjust an OFF time (endingtime) of the first and second switching pulses Pa and Pb.

The driving circuit 31 includes two PNP transistors Q1 and Q2, four NPNtransistors Q3, Q4, Q5, and Q6, four diodes D1, D2, D3, and D4, andeight resistor elements R1, R2, R3, R4, . . . , and R8 and forms anelectrical circuit by the wirings illustrated in FIG. 3. With thisconfiguration, when a control signal (a control command) Cc is appliedto the switching pulse generation unit 33, a first switching pulse Paillustrated in FIG. 2(a) is applied to a base of the NPN transistor Q3,and a second switching pulse Pb illustrated in FIG. 2(b) is applied to abase of the NPN transistor Q5. As a result, a driving pulse Psillustrated in FIG. 2(c) is applied across both ends of the driving coil6. The driving pulse Ps has a waveform which, except for the magnitude,is identical to a pulse waveform obtained by combining the firstswitching pulse Pa and the second switching pulse Pb of which thepositive and negative polarities are inverted.

Due to this, when the first switching pulse Pa is turned ON, a forwardcurrent Ii [A] flows into the driving coil 6. As a result, since thedriving coil 6 is excited in a forward direction and an energizationtorque Tfd is generated by the Lorentz force due to the Fleming'sleft-hand rule, the movable body portion Sm starts rotating toward thefirst position Xa while overcoming a holding torque Tfc between theattracting piece portion 11 bs and the magnet 8 b at the second positionXa. After that, the energization torque Tfd increases and reaches thelargest torque at a central position. When energization is continued,the movable body portion Sm is accelerated by the energization torqueTfd and reaches the first position Xa approximately at the highestspeed. That is, the movable body portion Sm is switched to the firstposition Xa. Since the magnetic flux density decreases at the firstposition Xa due to the influence of a magnetic circuit, the magnitude ofthe energization torque Tfd also decreases.

On the other hand, when the second switching pulse Pb is turned ON, abackward current −Ii [A] flows into the driving coil 6. As a result,since the driving coil 6 is excited in a backward direction and theLorentz force due to the Fleming's left-hand rule is generated, themovable body portion Sm is displaced toward the second position Xb andis switched to the second position Xb by an action similar to that ofthe case in which the movable body portion Sm is rotated toward thefirst position Xa.

In FIG. 14, magnetic lines of force Ff in the magnetic circuit when theforward current Ii disappears and the movable body portion Sm is stoppedat the second position Xa by the self-holding function of theself-holding mechanism 11 a are illustrated by dot-lines arrows.

In this case, magnetic lines of force Ff from the N pole of the magnet 8a pass through the inner space of the casing 2 and the lid portion 2 cto reach the S pole of the other magnet 8 b. The lid portion 2 cincludes the attracting piece portion 11 as integrally formed with thelid portion 2 c. Moreover, the magnetic lines of force Ff having passedthrough the inside of the lid portion 2 c pass through the frame portion2 m and pass through the air gap between the frame portion 2 m and therotor yoke 7. After that, the magnetic lines of force Ff pass throughthe rotor yoke 7 to reach the S pole of the magnet 8 a. On the otherhand, the magnetic lines of force Ff from the N pole of the magnet 8 bpass through the rotor yoke 7 to reach the S pole of the magnet 8 a andpass through the air gap between the rotor yoke 7 and the frame portion2 m. After that, the magnetic lines of force Ff pass through the frameportion 2 m and pass through the air gap between the frame portion 2 mand the rotor yoke 7 from the frame portion 2 m. After that, themagnetic lines of force Ff pass through the rotor yoke 7 to reach the Spole of the magnet 8 a. Moreover, the magnetic lines of force Ff havingpassed through the frame portion 2 m pass through the lid portion 2 e topass through the inner space of the casing 2 to reach the S pole of themagnet 8 b.

In this manner, even when the driving coil 6 is not excited, the distalend in the rotation direction Fr of the magnet 8 a and the attractingpiece portion 11 as approach at the shortest distance Ls (see FIG. 13)and the magnet 8 a and the attracting piece portion 11 as formed of amagnetic material attract each other. As illustrated in FIGS. 8 and 11,the position of the movable body portion Sm is restricted by therestricting stopper mechanism 10 a. That is, the restricting surfaceportion 13 a of the movable block portion 13 of the movable body portionSm makes contact with the inner surface 2 a of the casing 2 whereby theposition thereof is restricted. As a result, the movable body portion Smis held at the first position Xa by the restricting stopper mechanism 10a and the self-holding mechanism 11 a. Similarly, when the movable bodyportion Sm is displaced to the second position Xb, the movable bodyportion Sm is held at the second position Xb by a similar action.

While a basic operation of the rotary solenoid 1 according to the firstembodiment which uses the driving device 30 has been described, theillustrated driving device 30 can be used similarly in the rotarysolenoid 1 according to the second embodiment.

Particularly, in the second embodiment, since the magnetic attractionforce in the axial direction Fs can be decreased remarkably, frictionbetween the bearing portions 3 f and 3 r and the movable body portion Smcan be reduced remarkably, and the movable body portion Sm can reach thefirst position Xa (or the second position Xb) quickly (smoothly) afterthe driving pulse Ps is canceled. Moreover, in the second embodiment,although a magnetic material is inserted in the inner space of thedriving coil 6, when the cross-sectional area vertical to the axialdirection of the attracting piece 16 is set to the range of 0.1 to 10[%]of the cross-sectional area vertical to the axial direction in the innerspace of the driving coil 6, since increase in the inductance isapproximately 50[%] at most, the driving coil can be regardedsubstantially as an air-cored coil as will be described later when thiscondition is satisfied.

On the other hand, the rotary solenoid 1 according to the first andsecond embodiments can be used as a two-position switching deviceillustrated in FIGS. 16 and 17 as an example of a use method.

FIGS. 16 and 17 illustrate an overview of a banknote sorting device 50that sorts banknotes Mo conveyed along a conveying path 51 to a firstpassage 52 or a second passage 53. The banknote sorting device 50 has aconfiguration in which the rotary solenoid 1 is provided in a branchportion of three paths of the conveying path 51, the first entry passage52, and the second entry passage 53, and a flapper unit 41 is providedin the rotation shaft 4 of the rotary solenoid 1. The flapper unit 41 ispreferably formed as light as possible using a plastic material or thelike. The flapper unit 41 includes a base portion 41 m providedcoaxially at the distal end of the rotation shaft 4 and a pair offlapper portions 41 f provided to be separated in the axial direction ofthe base portion 41 m.

Due to this, in FIG. 16, when the flapper portions 41 f are switched toa position (the first position Xa) indicated by a solid line rotated inthe counter-clockwise direction, since the conveying path 51 and thefirst entry passage 52 are connected, a banknote Mo conveyed along theconveying path 51 can enter the first entry passage 52 in the directionindicated by arrow Fc. When the flapper portions 41 f are switched to aposition (the second position Xb) indicated by an imaginary line rotatedin the clockwise direction, since the conveying path 51 and the secondentry passage 53 are connected, a banknote Mo conveyed along theconveying path 51 can enter the second entry passage 53 in the directionindicated by arrow Fce.

When the rotary solenoid 1 is used for switching the flapper unit 41 ofthe banknote sorting device 50, the rotary solenoid 1 needs to securereliability in realizing stable and reliable switching based on acertain degree of output torque. Moreover, since the rotary solenoid 1needs to be arranged in a limited installation space, it is necessary torealize a compact size as much as possible and to realize high-speedprocessing (fast operations) since it is necessary to increase thenumber of processed items as much as possible. Furthermore, since therotary solenoid 1 uses electric power, it is necessary to reduce powerconsumption basically and to improve energy-saving properties andeconomic efficiency.

The rotary solenoid 1 according to the first and second embodiments canmeet the demands by an approach in a mechanical structure and can meetthe demands by an approach in a control method to be described later(that is, the drive control method according to the present invention).

Drive Control Method

Next, a drive control method according to the present invention suitablefor use in the rotary solenoid 1 according to the first and secondembodiments will be described with reference to FIGS. 1 to 7. FIGS. 1 to7 illustrate a case in which the drive control method is applied to therotary solenoid 1 of the first embodiment.

First, a conventionally general drive control method will be describedin order to facilitate understanding of the drive control methodaccording to the present invention.

FIG. 4 illustrates the change characteristics of a forward current Ii[A] with respect to time [ms] when a positive-side pulse Pp of a drivingpulse Ps illustrated in FIG. 2(c) is applied to the driving coil 6 bythe first switching pulse Pa illustrated in FIG. 2(a). In the rotarysolenoid 1 according to the first embodiment, since the fixed bodyportion Sc is formed using the driving coil 6, as described above, theinductance of the driving coil 6 can be set to a very small value ofseveral mH proportional to the permeability in the inner space of thedriving coil 6.

Therefore, a very fast response speed can be realized in such a way thatthe current can be raised up to a saturation current (in the illustratedexample, 1.0 [A]) substantially instantaneously like the forward currentIi illustrated in FIG. 4 when a driving voltage based on thepositive-side pulse Pp is applied.

In FIG. 4, a current characteristic curve when an iron plate issuperimposed on the back surface of the driving coil 6 is indicated byIip.

Moreover, a current characteristic curve when an iron core is insertedapproximately to a half part of an air core portion of the driving coil6 is indicated by Iss. Furthermore, a current characteristic curve whenan iron core that fills the inner space is inserted into the inner sideof the driving coil 6 is indicated by Ism. As understood from FIG. 4,particularly, the characteristic curve Iip provides characteristicsequivalent to those of the characteristic curve from the viewpoint thata fast response speed is obtained. Therefore, the driving coil 6 whichuses an air-cored coil is a concept including a case in which an ironplate is superimposed on the back surface of the air-cored coil as wellas a case in which a magnetic material is not added to the air-coredcoil.

In the case of the rotary solenoid 1 illustrated in FIGS. 16 and 17according to the second embodiment, although the attracting piece 16 (aniron core) is inserted into the inner space of the driving coil 6, theinductance when a small iron core having an area occupying 10[%] orsmaller of the area of the inner space is inserted is substantiallyequal to or smaller than the inductance when an iron plate issuperimposed on the back surface of the air-cored coil. The currentcharacteristic curve of this case is substantially the same as lip.Therefore, the driving coil 6 can be regarded as the driving coil 6which uses an air-cored coil as long as this condition is satisfied.

On the other hand, the energization period Tp of the positive-side pulsePp is set in the following manner. An energization period Tr indicatedby an imaginary line in FIG. 2(c) is a well-known general energizationperiod and illustrates a case in which the rotary solenoid is energizedin the entire rotation angle range Zm from the second position Xb to thefirst position Xa. Therefore, in this case, a drive control method basedon so-called full energization control is realized such that thepositive-side pulse Pp is applied, the movable body portion Sm at thesecond position Xb is rotated to reach the first position Xa, andapplication of the positive-side pulse Pp is stopped at a timing wherethe movable body portion Sm is stable.

In contrast, the drive control method based on the present embodiment isa drive control method based on so-called initial energization controlin which energization is controlled according to the time elapsedhalfway. The energization period Tp of the positive-side pulse Ppindicated by a solid line in FIG. 2 is control that follows the drivecontrol method based on the present invention. In this case, theenergization period Tp is a period in which the positive-side pulse Ppis applied and the positive-side pulse Pp is turned OFF when therotating position of the movable body portion Sm at the second positionXb reaches an intermediate position (specifically, an intermediateposition (an intermediate timing) at which the movable body portion Smis rotated from the second position Xb by 10 to 50[%] of the rotationangle range Zm when the rotation angle range Zm from the second positionXb to the first position Xa is 100[%]).

Hereinafter, a specific drive control method according to the presentembodiment will be described based on the flowchart illustrated in FIG.1 by referring to FIGS. 2 to 7.

FIG. 5 is a diagram illustrating the change characteristics of therotation angle [O] of the movable body portion Sm with respect to time[ms] including a comparative example when the rotary solenoid 1according to the present embodiment is driven by the driving device 30.FIG. 6 is a diagram for describing the principle of the changecharacteristics of the rotation angle [°] of the movable body portion Smwith respect to time [ms]. FIG. 7 is a diagram illustrating changecharacteristics of an output torque [N·m] with respect to the rotationangle [° ] when the movable body portion Sm is rotated.

First, a power switch (not illustrated) is turned ON (step S1). It isassumed that the movable body portion Sm of the rotary solenoid 1 stopsat the second position Xb (that is, the movable body portion Sm is in aself-holding state at the second position Xb). Moreover, it is assumedthat the control signal (control command) Cc illustrated in FIG. 3 isapplied to the switching pulse generation unit 33 (step S2).

When the control signal Cc is applied, first, the first switching pulsePa illustrated in FIG. 2(a) is applied to the base of the NPN transistorQ3 (step S3). In this way, a driving voltage based on the driving pulsePs (the positive-side pulse Pp) illustrated in FIG. 2(c) is applied tothe driving coil 6. As a result, the forward current Ii [A] is suppliedto the driving coil 6, and the driving coil 6 is excited in a forwarddirection (steps S5 and S6). When the driving coil 6 is excited in theforward direction, since an energization torque Tfd is generated by theLorentz force due to the Fleming's left-hand rule, the movable bodyportion Sm starts rotating toward the first position Xa while overcominga holding torque Tfc between the attracting piece portion 11 bs and themagnet 8 b at the second position Xa (step S7).

In this way, the positive-side pulse Pp is turned OFF when the movablebody portion reaches an intermediate position (that is, a predeterminedintermediate position Px) between the second position Xb and the firstposition Xa like a change characteristic Xi indicated by a solid line inFIG. 5 (steps S8 and S9). A rotation angle at the illustratedintermediate position Px is approximately 4.3 [°], and the rotationangle range Zm is approximately 22[%]. This intermediate position Pxcorresponds to an energization period Tp which is approximately 4 [ms].Even when the excitation of the driving coil 6 is stopped at theintermediate position Px, the movable body portion Sm continues rotatingas it does due to the inertial force (moment of inertia) (step S10).Moreover, the movable body portion Sm is displaced to the first positionXa due to the attraction of the magnet 8 a and the attracting pieceportion 11 as when the movable body portion Sm approaches the firstposition Xa (step S11). In this way, when the movable body portion Smreaches the first position Xa, the displacement is restricted by therestricting stopper mechanism 10 a, and the movable body portion Sm isattracted by the self-holding mechanism 11 a and is stopped at theintended first position Xa (steps S12 and S13). The intermediateposition may be detected directly by a sensor including switches and maybe detected indirectly via the elapsed time or the like.

In this case, the movable body portion Sm performs linear displacement(that is, constant-speed movement) from the intermediate position. Pxlike the change characteristic Xi illustrated in FIG. 5. Therefore, evenif the movable body portion Sm bounces a little at the first positionXa, the number and the magnitude of bounces decrease, and the movablebody portion Sm is held at the first position Xa at approximately 13[ms] as illustrated in FIG. 5. It is preferable that a period four timesor longer the response time constant (in the illustrated example, 0.5[ms]) of the current Ii is secured as the energization period Tp. Inthis way, since a current that is 98[%] or more of the saturationcurrent can be secured, the movable body portion Sm can be acceleratedas close as the largest torque.

A change characteristic Xr indicated by an imaginary line in FIG. 5indicates a driving pulse when the conventionally general drive controlis performed. In this case, since the driving coil 6 of the rotarysolenoid 1 is excited by the full energization control (the energizationperiod Tr in FIG. 2(c)), the movable body portion Sm is accelerated by atorque exceeding a holding torque Tfc based on the attraction of theattracting piece portion 11 bs and the magnet 8 b at the second positionXb, and the movable body portion Sm moves from the second position Xb toreach the first position Xa in approximately 8 [ms], bouncesapproximately twice repeatedly, and is self-held after approximately 12[ms] as indicated by the change characteristic Xr indicated by animaginary line in FIG. 5. In this case, a range in which the movablebody portion Sm rotates is the rotation angle range Zm and is 20 [O] inthe illustrated example. Moreover, after the movable body portion Smreaches the first position Xa, excitation is stopped after elapse ofapproximately 20 [ms] in order to avoid burning of the driving coil 6,and after that, non-energization is maintained for a period ofapproximately 80 [ms] or more. The first switching pulse used for thisfull energization control is the imaginary line Par illustrated in FIG.2(a).

In this case, the displacement of the movable body portion Sm is anaccelerating displacement based on a quadric function like the channelXr illustrated in FIG. 5. Due to this, when the movable body portion Smreaches the first position Xa and the restricting surface portion 13 acollides with the inner surface 2 a, since a large bounce occurs, themovable body portion Sm enters a holding state at a time point at whichthis bounce is settled to some extent. Therefore, after the holdingstate is created, the positive-side pulse Pp is turned OFF after theelapse of a predetermined period. When the movable body portion Smreaches the first position Xa, although the bounce is suppressed as muchas possible by voltage suppression control, brake pulse-based control,or the like, a certain degree of bounce is inevitable.

When processing of installed devices and the like is continued, thedriving pulse (the negative-side pulse Pn) illustrated in FIG. 2(c) isapplied, and by the same action as the positive-side pulse Pp, themovable body portion Sm is displaced from the first position Xa to thesecond position Xb and is switched to the second position Xb, and theabove-described operations are executed repeatedly (steps S14, S2, S3,S4, S5, and so on).

When all the intended operations end, the power switch is turned OFF(steps S14 and S15).

Even when the control method according to the present embodiment isperformed in this manner, although the time taken for displacement ofthe movable body portion Sm does not change too much as compared to acase in which general full energization control is performed, theenergization period Tp can be reduced approximately by ⅕ and powerconsumption can be reduced by ⅕.

In the illustrated example, since the response time constant of thecurrent is 0.5 [ms], when the power consumption is reduced by ⅕, atemperature rise of the driving coil 6 is reduced by ⅕. Therefore, whenthe temperature rise of the driving coil 6 during full energizationcontrol where the energization period Tr is 20 [ms] (duty ratio: 20%) is100 [° C.], a temperature rise of the driving coil 6 during initialenergization control where the energization period Tp is 4 [ms] (dutyratio: 4%) is suppressed approximately to 20 [° C.].

If the temperature rise of the driving coil 6 can be suppressed to 20 [°C.], since a resistance rise remains at approximately 8[%], a troublesuch as burning may not occur, a decrease in the output torque has alevel so small as to be negligible, and the structure can be simplified.As for decrease in output torque, when the driving coil 6 is driven by aconstant-voltage circuit and a temperature rise of the driving coil 6 is100 [° C.], since the output torque is inversely proportional to aresistance, the resistance increases by 40[%] and the output torque isapproximately 70[%].

A range of timings at which the first switching pulse Pa is turned OFF(canceled) is preferably set to a timing at which a rotation angle fromthe second position Xb reaches 10 to 50[%] of the rotation angle rangeZm as illustrated in FIG. 6. In FIGS. 5 to 7, a selectable cancellationrange Ze (that is, the range of 10 to 50[%]) is indicated by hatchedlines.

In this case, when the rotation angle is smaller than 10[%], theinfluence of a self-holding force at the second position Xb serving as astarting position acts greatly and there is little margin for copingwith load variations. When the rotation angle is equal to or larger than50[%], since the driving coil 6 at the first position Xa is not excited,the self-holding force at the first pixel of interest Xa is small andthe bounce increases. Therefore, the control approaches the fullenergization control at the rotation angle of 50[%] or larger, and as aresult, the energization period increases. From the above-mentionedreasons, it is preferable that the rotation angle from the second pixelof interest Xb is selected from the range of 10 to 50[%]. In this way,it is possible to realize low power consumption, small impact, and lownoise while avoiding decrease in a response speed.

In FIG. 6, Pd indicates a canceling position which occurs at a relativeearly stage and this canceling position Pd corresponds to approximately5[%] of the rotation angle range Zm. When the positive-side pulse Pp isturned OFF at this canceling position Pd, the movable body portion Sm isdisplaced along a change characteristics line Kd which is a tangentialline of a change characteristic curve Xr at the canceling position Pd.Therefore, an arrival time td at the first position Xa on an extensionline of the change characteristic line Kd is approximately 18 [ms]. Inthis case, since the arrival time td is longer than an arrival time to(12 [ms]) during the full energization control illustrated in FIG. 5,the response speed decreases and the demand for fast operations cannotbe met. Furthermore, the pulse is turned OFF before the originalenergization torque Tfd occurs.

Pu indicates a canceling position which occurs at a relatively latestage and this canceling position Pu corresponds to approximately 50[%]of the rotation angle range Zm. When the positive-side pulse Pp isturned OFF at this canceling position Pu, control is performedsubstantially similar to the full energization control (the changecharacteristics Xr). That is, the movable body portion Sm is displacedalong a change characteristic line Ku which is a tangential line of thechange characteristic curve Xr at the canceling position Pu. Therefore,an arrival time to at the first position Xa on an extension line of thechange characteristic line Ku is approximately 8 [ms]. In this case,although control is similar to the full energization control, sincecollision occurs in a non-energized state at the first position, thestability may become worse. Pm indicates a canceling position located inthe middle of the canceling positions Pd and Pu, and Km indicates achange characteristic line which is a tangential line at the cancelingposition Pm.

The holding torque Tfc generated by the attraction between the magnet 8a and the attracting piece portion 11 as at the first position Xa can beset arbitrarily depending on the use or the like, when the controlmethod according to the present embodiment is used, the holding torqueTfc is preferably set to 10 to 50[%] of the energization torque Tfdgenerated during energization of the driving coil 6. When theenergization torque Tfd at the first position Xa is to be set to 50 to80[%] of a central position where a largest torque (the energizationtorque Tfd) is generated, it is necessary to activate the driving coilreliably. Therefore, it is preferable to set the holding torque Tfc to50[%] or smaller of the largest energization torque Tfd at the centralposition. Moreover, in order to avoid the influence of vibration or thelike and to secure a reliable self-holding force in a non-energizedstate, the holding torque Tfc is preferably set to 10[%] or more of theenergization torque Tfd.

FIG. 7 illustrates change characteristics when the holding torque Tfc isset to 10 [%] and 50[%]. In FIG. 7, Ti indicates change characteristicsof an output torque (energization torque+holding torque) when theholding torque Tfc is set to 50[%] of the energization torque Tfd andthe pulse is turned OFF in a setting range Ze of 10 to 50 [%]. FIG. 7also illustrates, as a comparative example, change characteristics Trwhen a holding torque based on the attracting piece portion 11 as is notpresent and a general driving pulse corresponding to the characteristiccurve Xr in FIG. 5 is applied over the entire period. FIG. 7 alsoillustrates change characteristics Ths of the holding torque when theholding torque is set to 10[%] of the torque generated duringenergization of the driving coil 5, and change characteristics Thm ofthe holding torque when the holding torque is set to 50[%] of the torquegenerated during energization of the driving coil 6. FIG. 7 alsoillustrates characteristics Trs which combine the change characteristicsTr and Ths and characteristics Tim which combine the changecharacteristics Tr and Thm.

While operations have been described mainly based on the positive-sidepulse Pp, when the negative-side pulse Pn illustrated in FIG. 2(c) isapplied to switch the movable body portion Sm at the first position Xato the second position Xb, basic operations are the same as the case ofthe positive-side pulse Pp.

While the best mode embodiment has been described in detail, the presentinvention is not limited to such an embodiment, but arbitrary changes,additions, and omissions can occur in detailed configuration, shape,material, number and quantity, and method without departing from thegist of the present invention.

For example, although the first embodiment (including the modification)and the second embodiment have been illustrated as the rotary solenoid 1to which the drive control method according to the present invention canbe applied. However, the present invention is not limited to theseembodiments but can be applied to various rotary solenoids.Particularly, as a basic form, the present invention can be applied tovarious rotary solenoids 1 including: the fixed body portion Sc havingthe casing 2 in which the pair of bearing portions 3 f and 3 rpositioned on front and rear sides are provided; and the movable bodyportion Sm having the rotation shaft 4 rotatably supported by the pairof bearing portions 3 f and 3 r, wherein the movable body portion Sm canreciprocate in the rotation angle range Zm between the first position X1and the second position X2 by energization control of the driving coil 6and can be stopped at the first position Xa and the second position Xbby the pair of self-holding mechanisms 11 a and 11 b by the restrictionof the pair of restricting stopper mechanisms 10 a and 10 b and theattraction of the magnets 8 a and 8 b. The intermediate position Xp maybe set directly by a specific position and may be set indirectly by atime corresponding to the position. Moreover, well-known stop controlsuch as voltage suppression control, brake pulse-based control, or thelike may be performed as necessary when the movable body portion Smapproaches a stopping position. On the other hand, a case in which thepair of restricting stopper mechanisms 10 a and 10 b that make contactwith each other to restrict the rotation angle range Zm of the movablebody portion Sm are shared by the fixed body portion Sc and the movablebody portion Sm has been illustrated. However, the restricting stoppermechanisms 10 a and 10 b may be provided separately for the fixed bodyportion and the movable body portion and may be provided in the rotationshaft 4 protruding outward from the casing 2. Moreover, a case in whichthe movable block portion 13 formed of a non-magnetic material to holdthe rotor yoke 7 and the magnet portion 8 by being fixed to the rotationshaft 4 is provided in the movable body portion Sm has been illustrated.However, the movable block portion 13 may not be used. Furthermore, acase in which the component holding portion 14 that holds one or two ormore circuit components Pc connected to the driving coil 6 is providedin the fixed block portion 12 has been illustrated. However, thecomponent holding portion 14 is optional. On the other hand, a case inwhich the self-holding mechanisms 11 a and 11 b that hold the positionof the movable body portion Sm by attraction to the movable body portionSm at both end positions Xa and Xb of the rotation angle range Zm areshared by the casing 2 has been illustrated. However, an additionalcomponent may be attached.

INDUSTRIAL APPLICABILITY

The drive control method according to the present invention can be usedwhen controlling the driving of various rotary solenoids includingcontrolling the driving of two-position switching actuators in variousdevices having various switching functions such as a function of sortingmoney, banknotes, and the like, a function of sorting postal matter, afunction of switching a conveying path of printed materials, and anoptical path switching function.

The invention claimed is:
 1. A rotary solenoid drive control method forcontrolling driving of a rotary solenoid including: a fixed body portionhaving a casing in which a pair of bearing portions positioned on frontand rear sides are provided; and a movable body portion having arotation shaft rotatably supported by the pair of bearing portions,wherein the movable body portion is configured to reciprocate in arotation angle range between a first position and a second positionaccording to energization control of a driving coil and to be stopped atthe first position and the second position by a pair of self-holdingmechanisms by restriction of a pair of restricting stopper mechanismsand attraction of magnets, and when controlling switching from thesecond position (or the first position) to the first position (or thesecond position), after a driving voltage based on a driving pulse isapplied to the driving coil, if the movable body portion has reached apredetermined intermediate position in 10 to 50[%] of the rotation anglerange, control is performed so that application of the driving voltageis stopped.
 2. The rotary solenoid drive control method according toclaim 1, wherein the fixed body portion includes a casing formed of amagnetic material and a driving coil which uses an air-cored coil fixedto an inner surface of the casing, which is a surface orthogonal to anaxial direction of the rotation shaft, and wherein the movable bodyportion includes a rotor yoke having one end fixed to the rotation shaftand a magnet mechanism portion having a pair of magnets fixed to anopposing surface positioned on the other end of the rotor yoke, which isa surface opposing the driving coil, and disposed along a rotationdirection of the opposing surface.
 3. The rotary solenoid drive controlmethod according to claim 1, wherein the fixed body portion and themovable body portion share the restricting stopper mechanisms that makecontact with each other to restrict the movable body portion.
 4. Therotary solenoid drive control method according to claim 1, wherein thecasing shares the self-holding mechanisms that attract the movable bodyportion at the first position and the second position.
 5. The rotarysolenoid drive control method according to claim 1, wherein theself-holding mechanism includes an attracting piece portion thatprotrudes from a portion of the casing.
 6. The rotary solenoid drivecontrol method according to claim 1, wherein the movable body portionincludes a driving coil held by a movable block portion, the rotationshaft fixed to the movable block portion and disposed to be arranged inparallel to a center of the driving coil, and an attracting piece formedof a magnetic material and fixed to a predetermined position of themovable block portion, and wherein the fixed body portion includes acasing formed of a magnetic material, and a magnet mechanism portionhaving two sets of magnet portions fixed to inner surfaces of thecasing, disposed to oppose an end in an axial direction of the drivingcoil, and disposed to correspond to the first position and the secondposition of the movable body portion.
 7. The rotary solenoid drivecontrol method according to claim 6, wherein the magnet portion isformed of a single magnet disposed on one inner surface of the casing,opposing one end in the axial direction of the driving coil.
 8. Therotary solenoid drive control method according to claim 6, wherein themagnet portion is formed of a pair of magnets disposed on both opposinginner surfaces of the casing, opposing both ends in the axial directionof the driving coil.
 9. The rotary solenoid drive control methodaccording to claim 6, wherein a cross-sectional area vertical to anaxial direction of the attracting piece is set to a range of 0.1 to10[%] of a cross-sectional area vertical to an axial direction of aninner space of the driving coil.
 10. The rotary solenoid drive controlmethod according to claim 4, wherein the self-holding mechanism includesan attracting piece portion that protrudes from a portion of the casing.